Morphological and biochemical characteristics of Aeromonas punctata (hydrophila, liquefaciens) isolated from human sources.

The isolation of Aeromonas punctata (hydrophila, liquefaciens) from feces, throat, and sputum cultures is presented as further evidence that aeromonads are found in man. Morphological and biochemical studies of these strains indicate that the chief differences between the aeromonads and physiologically similar members of the Enterobacteriaceae are found in the polar arrangement of the flagella and in the production of oxidase by the former. The oxidase test should be performed on all paracolon-like bacteria, and a flagella stain should be employed when an oxidase-positive, gram-negative bacillus is isolated. Application of these tests will undoubtedly result in more frequent identification of Aeromonas species from human sources.